1,226 research outputs found

    Women's secure hospital services: national bed numbers and distribution.

    Get PDF
    A mapping exercise as part of a pathway study of women in secure psychiatric services in the England and Wales was conducted. It aimed to (i) establish the extent and range of secure service provision for women nationally and (ii) establish the present and future care needs and pathways of care of women mentally disordered offenders (MDO) currently in low, medium and enhanced medium secure care. The study identified 589 medium secure beds, 46 enhanced medium secure beds (WEMSS) and 990 low secure beds for women nationally. Of the 589 medium secure beds, the majority (309, 52%) are in the NHS and under half (280, 48%) are in the independent sector (IS). The distribution of low secure beds is in the opposite direction, the majority (745, 75%) being in the IS and 254 (25%) in the NHS. Medium secure provision for women has grown over the past decade, but comparative data for low secure provision are not available. Most women are now in single sex facilities although a small number of mixed sex units remain. The findings have implications for the future commissioning of secure services for women

    Intra-hour cloud index forecasting with data assimilation

    Get PDF
    We introduce a computational framework to forecast cloud index (CI)fields for up to one hour on a spatial domain that covers a city. Such intra-hour CI forecasts are important to produce solar power forecasts of utility scale solar power and distributed rooftop solar. Our method combines a 2D advection model with cloud motion vectors (CMVs)derived from a mesoscale numerical weather prediction (NWP)model and sparse optical flow acting on successive, geostationary satellite images. We use ensemble data assimilation to combine these sources of cloud motion information based on the uncertainty of each data source. Our technique produces forecasts that have similar or lower root mean square error than reference techniques that use only optical flow, NWP CMV fields, or persistence. We describe how the method operates on three representative case studies and present results from 39 cloudy days

    High-fidelity quantum logic gates using trapped-ion hyperfine qubits

    Full text link
    We demonstrate laser-driven two-qubit and single-qubit logic gates with fidelities 99.9(1)% and 99.9934(3)% respectively, significantly above the approximately 99% minimum threshold level required for fault-tolerant quantum computation, using qubits stored in hyperfine ground states of calcium-43 ions held in a room-temperature trap. We study the speed/fidelity trade-off for the two-qubit gate, for gate times between 3.8μ\mus and 520μ\mus, and develop a theoretical error model which is consistent with the data and which allows us to identify the principal technical sources of infidelity.Comment: 1 trap, 2 ions, 3 nines. Detailed write-up of arXiv:1406.5473 including single-qubit gate data als

    Assessing the implementation of BIM – an information systems approach

    Get PDF
    Much attention has been paid to measuring the perceived benefits of Building Information Modelling (BIM). Yet despite an increase its adoption throughout the construction industry, important links between implementation, support and benefits are yet to be explored. We examine the constitutive elements of the BIM implementation process of two case studies implementing and using BIM: The first is a large urban regeneration project and the second is a healthcare project. A well-recognised model of system success is mobilised from the field of information systems (IS) to reveal that irrespective of project size and type, BIM benefits are confined to technically discrete productivity and efficiency gains when there is limited focus on the organisational aspects of BIM adoption. This paper focuses on the disconnections between organisational and project level BIM implementation using the DeLone and McLean Model as an analytical framework to systematically examine the benefits of BIM to each project in relation to the implementation approach employed. This study highlights the significance of these interdependencies and argues for a more comprehensive approach to BIM benefits capture that recognises this to usefully inform implementation strategy development

    High-fidelity trapped-ion quantum logic using near-field microwaves

    Full text link
    We demonstrate a two-qubit logic gate driven by near-field microwaves in a room-temperature microfabricated ion trap. We measure a gate fidelity of 99.7(1)\%, which is above the minimum threshold required for fault-tolerant quantum computing. The gate is applied directly to 43^{43}Ca+^+ "atomic clock" qubits (coherence time T2∗≈50 sT_2^*\approx 50\,\mathrm{s}) using the microwave magnetic field gradient produced by a trap electrode. We introduce a dynamically-decoupled gate method, which stabilizes the qubits against fluctuating a.c.\ Zeeman shifts and avoids the need to null the microwave field

    Magnetic field stabilization system for atomic physics experiments

    Full text link
    Atomic physics experiments commonly use millitesla-scale magnetic fields to provide a quantization axis. As atomic transition frequencies depend on the amplitude of this field, many experiments require a stable absolute field. Most setups use electromagnets, which require a power supply stability not usually met by commercially available units. We demonstrate stabilization of a field of 14.6 mT to 4.3 nT rms noise (0.29 ppm), compared to noise of ≳\gtrsim 100 nT without any stabilization. The rms noise is measured using a field-dependent hyperfine transition in a single 43^{43}Ca+^+ ion held in a Paul trap at the centre of the magnetic field coils. For the 43^{43}Ca+^+ "atomic clock" qubit transition at 14.6 mT, which depends on the field only in second order, this would yield a projected coherence time of many hours. Our system consists of a feedback loop and a feedforward circuit that control the current through the field coils and could easily be adapted to other field amplitudes, making it suitable for other applications such as neutral atom traps.Comment: 6 pages, 5 figure

    A microfabricated ion trap with integrated microwave circuitry

    Full text link
    We describe the design, fabrication and testing of a surface-electrode ion trap, which incorporates microwave waveguides, resonators and coupling elements for the manipulation of trapped ion qubits using near-field microwaves. The trap is optimised to give a large microwave field gradient to allow state-dependent manipulation of the ions' motional degrees of freedom, the key to multiqubit entanglement. The microwave field near the centre of the trap is characterised by driving hyperfine transitions in a single laser-cooled 43Ca+ ion.Comment: 4 pages, 5 figure

    Microwave control electrodes for scalable, parallel, single-qubit operations in a surface-electrode ion trap

    Full text link
    We propose a surface ion trap design incorporating microwave control electrodes for near-field single-qubit control. The electrodes are arranged so as to provide arbitrary frequency, amplitude and polarization control of the microwave field in one trap zone, while a similar set of electrodes is used to null the residual microwave field in a neighbouring zone. The geometry is chosen to reduce the residual field to the 0.5% level without nulling fields; with nulling, the crosstalk may be kept close to the 0.01% level for realistic microwave amplitude and phase drift. Using standard photolithography and electroplating techniques, we have fabricated a proof-of-principle electrode array with two trapping zones. We discuss requirements for the microwave drive system and prospects for scalability to a large two-dimensional trap array.Comment: 8 pages, 6 figure
    • …
    corecore